FIELD OF THE INVENTION
Generally, this invention relates to organic-inorganic perovskites of the types A.sub.2 MX.sub.4 and AMX.sub.3 where A=an organic cation, X=a halogen and "M"=a divalent metal cation. More particularly, this invention relates to organic-inorganic perovskites of the A.sub.2 MX.sub.4 and AMX.sub.3 types having a divalent rare earth metal atom in the M site.